The United States was tottering last night on the brink of a new racial crisis, pitting black against white in the nation's cities, which turned Los Angeles into a war zone on Wednesday night. In Atlanta, the last resting place of Martin Luther King, students went on a copycat rampage in a shopping mall. Police reported a number of beatings and arrests. In Washington, President Bush went on television to appeal for calm, trying to contain a potentially explosive situation nationwide after the acquittal of four Los Angeles police officers accused of beating a black motorist, Rodney King.

In Los Angeles, 2,000 armed national guardsmen moved into the streets yesterday to reinforce police and hundreds of California Highway Patrol officers. The governor, Pete Wilson, ordered the deployment of 2,000 more men. Armed national guardsmen, some in the desert camouflage of the Gulf War, were deployed with their armoured vehicles at shopping malls along Martin Luther King boulevard, just north of the Watts ghetto.

Authorities in the city said the latest casualty toll from the rioting included 16 dead and at least 200 wounded. The mayor, Tom Bradley, declared a state of emergency and a dusk-to-dawn curfew was imposed on the city. Over 300 people were arrested and gun sales were suspended. In the 15 hours ending at midday yesterday, firefighters responded to 1,200 fires. Firefighters reported sporadic sniper fire, and one firefighter was hit. Police said two snipers had been shot dead.

The rioting followed a jury's acquittal of four white policemen on charges of assault and of using excessive force in arresting Mr King in March last year. The arrest was videotaped by a witness and showed Mr King writhing on the ground as he was kicked, shocked with a stun gun and clubbed 56 times. His leg and facial bones were broken. Despite this, the officers were found not guilty by a jury of 10 whites, one Hispanic and one Asian American.

Much of Wednesday night's violence appeared to have been caused by groups of black men who raged through the city, pulling motorists from cars and beating them, attacking police, smashing shop windows and setting fires. But whites and Hispanics also joined in. It was the worst violence in Los Angeles since the 1965 riots in the Watts district in which 34 people were killed.

The Democratic presidential candidate, Bill Clinton, said the acquittal verdict left "a huge, gaping feeling that the system is broken and unfair". But one juror said Mr King had brought the beating on himself because he repeatedly resisted arrest after a car chase.